Abdominal exercise machines are popular amongst those exercisers desiring a strong core and preferring to perform machine-oriented exercise as opposed to sit-ups and other fundamental types of core exercises.
Abdominal exercise machines traditionally include a portion of the machine that moves to allow the user to contract his abdominal muscles. For instance, U.S. Pat. No. 4,387,893 describes a traditional clamshell structure with upper and lower movement arms that pivot toward each other about a single pivot axis. U.S. Pat. No. 5,056,779 describes an abdominal exercise machine with an upper movement arm that allows the user to contract his abdominal muscles.
Accordingly, there is a need to provide an abdominal exercise machine that includes upper and lower moving parts, with the parts moving in concert and in a manner that models or emulates the movement of a human spine during the contraction of the abdominal muscles.